AV got the Mayor elected - now he's voting against it

Get out and vote: Lib-Dem leader Nick Clegg believes AV is a small change that will make a big difference

After the expenses scandal I believe most Londoners want a new way of electing MPs that cleans up politics, makes MPs work harder and makes every vote count.

That is exactly what you get with the alternative vote.

The truth is AV is a small change that will make a big difference. It means that the winner has to be somebody who appeals to the majority, not a small minority.

Under first past the post, huge numbers of MPs are elected on just a fraction of the vote in their constituency. And politicians and parties compete for the votes of a few thousand people in a small number of marginal constituencies, ignoring everyone else.

Last year, more than two-thirds of MPs were elected with fewer than half the voters in their constituencies choosing them. In many cases, fewer than a third of an MP's constituents voted for them. That means most of us are represented by an MP whom most of us did not vote for. Where is the democracy in that? No wonder no other country in the EU uses first past the post.

AV means MPs will have to work harder to appeal to more people than before. They will have to reach out to people who were ignored under first past the post. They will no longer be able to rely on just their core supporters and ignore everyone else. They will be more legitimate and will carry a stronger mandate from a broader range of people.

Under the alternative vote, there will be fewer complacent MPs with jobs for life in safe seats. That means less chance of the sort of scandals that have disgraced politics recently.

It means people whose voices have been ignored will be listened to again. It means that parties will have to compete for votes in every corner of the country and not just those few marginal seats.

Under the alternative vote, you can use your vote positively. It means you can feel confident voting for the person or party you want to win and not have to think tactically about who can win.

So what have the arguments against AV been? Certainly not ones based on facts. Instead, there have been lies about the cost of "vote-counting machines" that don't exist and won't be needed. Claims that the alternative vote is too complex for the British people to understand, as if people are too dim to put 1-2-3 on a piece of paper. And the claim that AV helps extremists like the BNP. These are all false, but it's the last of these myths that is the most pernicious.

My Cabinet colleague, Baroness Warsi, has said that AV would give "more votes, more power, more long-term legitimacy for the BNP and other fringe parties". So how come the BNP is campaigning, as are the Tories, to keep first past the post?

This is what the BNP's deputy chairman Simon Darby had to say about it when he was explaining why his party was campaigning for a No vote: "We are never going to get our feet under the table under the AV system."

The members of the BNP aren't the only extremists to oppose change - the Communist Party is also defending the status quo.

The reason for this reaction by extremists is simple. The great advantage of the alternative vote is that it stops candidates from being elected simply by pandering to a specific group of people and ignoring the rest. When you need to aim for the support of half the people in your constituency it's not possible to target a minority of voters and hope their support gets you through. Extremists have no chance under AV.

We know it has long been the dream of the BNP to win a seat in London. Only last year Nick Griffin was hoping his own brand of extremist politics would land him the seat of Barking. He was soundly defeated, but we should not kid ourselves. The BNP will be back, looking for seats where they can create and exploit racial tension and where they can hope to get an MP elected with barely 30 per cent of the vote.

A Yes vote would be a no to racist parties.

The referendum allows London to slam the door in the face of the BNP for good. Its dream of taking advantage of the flaws in the current system will be over.

Here in the capital we know all about AV because it's what we use to elect the Mayor. If you didn't know that, it's probably because it's such a straightforward system that you've never had to think about it.

Yet, absurdly, Boris Johnson has decided to side with the No camp. Not only was Boris elected under an AV system, his Conservative Party used a version of it to elect its own leader, David Cameron - David Davis would have won if they had used first past the post - and they use it to select candidates too.

If it's good enough for the Conservatives, why don't they think it's good enough for you?

The alternative vote puts you back in charge. You get a bigger say in who your MP is, a bigger foothold in our democracy, a bigger stake in our country.

This city doesn't have any other elections on May 5 but that's not a reason to stay at home. In fact, it's a reason to get out and vote.

This is a once-in-a-generation opportunity. Never before have we been asked to decide how to elect the people whose job it is to represent us. In little more than a week, we have that chance.

Politics could change for the better on May 5. I hope everyone in London can be a part of that change. Don't let the rest of the country decide without you.